With continuous development and wide application of optical information technology, requirements for network traffic in various fields are growing. With continuous improvement of fiber optic network, how to achieve high-bandwidth long-distance information transmission of the optical fiber becomes a crucial problem in the field of information technology. A key to solve the problem is to improve an optical signal noise ratio in a fiber optic network system, and one of effective methods for improving the optical signal noise ratio is to replace an ordinary standard single-mode optical fiber with an ultra-low loss optical fiber. A loss of the optical fiber is caused by an impurity in its material. The loss can be reduced if content of the impurity in the material is reduced, which also leads to an increased transmission speed and a prolonged transmission distance. The number of signal regenerators for establishing an optical network can be reduced if the transmission distance is increased, thereby effectively reducing cost of establishing the optical network. For the above reasons, there are many studies on optical fiber characteristics and transmission performances of the ultra-low loss optical fiber currently. An SMF-28® ultra-low loss optical fiber produced by Corning Corporation and a Farband™ ultra fiber produced by Changfei Corporation are in commercial use. However, the ultra-low loss optical fiber has a greater development difficulty than an ordinary optical fiber or low loss optical fiber. Since the ultra-low loss optical fiber has a different section structure and a different manufacturing process, a development cycle is required for R&D staff to redesign a section structure and develop a new manufacturing process, thereby increasing the cost. Production and processing cost of the ultra-low loss optical fiber is also higher than that of the ordinary single-mode optical fiber, and an ultra-low loss optical fiber having an attenuation coefficient closer to a theoretical limit is more expensive.
For a large-scale optical network, it is unsuitable in terms of technique and cost to replace all standard single-mode optical fibers with the ultra-low loss optical fibers in a one-time step. The network operator prefers to gradually replacing the standard single-mode optical fiber in the existing optical network with the ultra-low loss optical fiber in a life cycle of the original optical fiber. Based on the foregoing, a study on an optical fiber replacement method for the optical network is lacked in the art, that is, a replaced optical fiber is not effectively selected according to the traffic load distribution and operational status of an optical network, thereby resulting in poor performance improvement of the optical network and a high cost for replacing optical fibers.